Method and system for authenticating telephone callers and avoiding unwanted calls

ABSTRACT

A service that handles incoming telephone calls without bothering the telephone subscriber is disclosed. The service permits a call to go through to a subscriber if the service determines that the call is not unwanted and the caller has been unauthenticated. The authentication is based on challenging the caller to prove its identity rather than relying on caller ID displays. Prospective callers pre-register with the service providing caller account information. When a caller is issued a challenge, the caller may prove its authenticity by supplying the challenge back to the service along with its registered information.

BACKGROUND OF THE INVENTION

The invention relates generally to the field of consumer protection andmore particularly, to protecting consumers from fraudulent solicitorsemploying telecommunications as a means of contact.

The unsolicited telephone call has become over many years an unwantednuisance to some individuals. Where unsolicited telephone calls were, insome cases, merely an annoying interruption of daily life, the callshave become, for some, a more troubling and dangerous prospect.Unscrupulous entities have for some time taken to using the telephoneand other forms of telecommunications as a means for scammingindividuals out of important resources such as money and morecontemporarily, out of one's identity.

One manner of combating against unsolicited calls involves using callerID services provided by a telephone provider. Examples may be seen inU.S. Pat. No. 6,618,473 to Davis and U.S. Publication No. 2004/0131164to Gould.

Unscrupulous entities may cheat a caller ID system by using techniquessuch as spoofing. Spoofing involves, in some instances, registering fakeidentities and telephone numbers with the caller ID service so that aspoofer's caller ID information fraudulently displays the origin of itscalls. Some spoofers send hoax calls pretending to be legitimateentities, such as a targeted individual's bank, and convince theindividual to provide sensitive information such as a social securitynumber and bank account number.

As may be seen, there is a need for a system and method of screening outcalls that employ authentication of the calls' origins.

SUMMARY OF THE INVENTION

A method of authenticating a source of a call from a caller to arecipient in a screening service comprises the steps of, generating acaller account with the service including registration of a calleridentity and registration of a digital signature associated with thecaller, recording the registered caller identity and the digitalsignature with an authenticator; intercepting the call by a screener;receiving a proposed caller identity by the screener from the callerduring the call, including a phone number associated with the source ofthe caller, issuing a challenge by the screener to the caller,encrypting the issued challenge and the proposed caller identity by thecaller using the digital signature, sending the encrypted challenge andthe proposed caller identity from the caller to the authenticator,decrypting the encrypted challenge and the proposed caller identity atthe authenticator and authenticating the source of the encryptedchallenge by comparing the digital signature sent with the encryptedchallenge against the digital signature registered in the calleraccount, forwarding the decrypted challenge and the proposed calleridentity to the screener, verifying the decrypted challenge and thecaller's registered caller identity match the issued challenge and theproposed caller identity received during the call, and passing the callto the recipient.

In another embodiment, a method of authenticating a source of a callfrom a caller to a recipient in a screening service includes,intercepting the call by a screener, receiving a caller identity by thescreener from the caller, verifying that the caller is registered to aphone number shown in the caller identity, issuing a challenge by thescreener to the caller and hanging up the call, sending a return phonecall from the screener to the caller using the phone number shown in thecaller identity, verifying that the caller is in possession of thechallenge; and passing the caller to the recipient.

In still yet another embodiment, a computer-readable medium forauthenticating a source of a communication from a sender to a recipientusing a screening service includes, software instructions for generatinga sender account sender registration service information with theservice including registration of a sender identification, a sendercommunication address a sender public key and a sender private key,software instructions for storing the sender registration informationwith an authenticator; software instructions for intercepting thecommunication by using a screener; software instructions for receivingfrom the sender the sender identification and the sender communicationaddress; software instructions for issuing an electronic challenge fromthe screener to the sender, software instructions for encrypting theelectronic challenge using the sender private key, encrypted by thesender; software instructions for receiving the encrypted electronicchallenge by the authenticator from the sender; software instructionsfor applying the registered sender public key to the sender private keyof the encrypted electronic challenge to decrypt the encryptedelectronic challenge, software instructions for blocking thecommunication if the step of applying the registered sender public keyto the private key of the encrypted electronic challenge fails todecrypt the challenge, software instructions for forwarding thedecrypted electronic challenge to the screener; software instructionsfor verifying with the screener the decrypted electronic challengematches the challenge issued by the screener, and software instructionsfor routing the call to the recipient.

In still yet another embodiment, a system for authenticating a source ofa telecommunication from a sender sent to a subscriber comprises a databank for storing subscriber information and sender registration data, ascreener in electronic intermediate communication between the sender andthe subscriber for intercepting the telecommunication, issuing achallenge to the sender and forwarding authenticated telecommunicationsto the subscriber; an authenticator in electronic communication with thedata bank and screener for authenticating the source of thetelecommunication by comparing the sender registration data stored inthe data bank to an encrypted message transmitted from the senderincluding the challenge issued by the screener and for forwarding anauthentication status to the screener; and telecommunication lines forforming a telecommunication network between the sender, the screener,the authenticator, the data bank, and the subscriber.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdrawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustrating a system according to one embodimentof the present invention;

FIG. 2 is a flow chart depicting a series of steps employed according toone embodiment of the present invention shown in FIG. 1; and

FIG. 3 is a flow chart depicting a series of steps employed according toanother embodiment of the present invention shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplatedmodes of carrying out the invention. The description is not to be takenin a limiting sense, but is made merely for the purpose of illustratingthe general principles of the invention, since the scope of theinvention is best defined by the appended claims.

In general, the invention may be employed as a service for screening outunauthorized solicitors in a telecommunication within either acommercial or personal setting or an interaction of the two. Theinvention may employ human-to-human interaction or utilize automationtools employing software to field communications between senders andrecipients of messages. One exemplary use includes a service providingscreening of impersonated hoax calls to private individuals where theservice weeds out callers that spoof their caller identity with aims toimpersonate a trusted business entity, such as a bank, and trick theprivate individuals out of personal information.

For illustrative purposes, one embodiment of the invention authenticatesa caller identity displayed by a caller. One embodiment of the inventionalso may include using a screener that issues a challenge to a callerthat the caller uses to respond to the service as proof of its identity.An embodiment of the invention may also include employing the use of adigital signature and an authenticator to verify a caller's identity bymeans of a voiced challenge and voice response from a secured center.For example, a caller may be requested to confirm its identity bysending a registered digital signature to the authenticator who mayconfirm if the caller satisfies criteria as a legitimate caller. Ascreener can then call the authenticator and receive the challenge backas a voiced proof of caller's authenticity. Additionally, one embodimentof the invention may use interaction by sending a return phone call tothe caller using the phone number shown in the caller's identity.

Accordingly, embodiments may take the form of an entirely hardwareembodiment, an entirely software embodiment (including firmware,resident software, micro-code, etc.) or an embodiment combining softwareand hardware aspects that may all generally be referred to herein as a“circuit,” “module” or “system.” Furthermore, embodiments may also takethe form of a computer program product embodied in any tangible mediumof expression having computer-usable program code embodied in themedium.

Any combination of one or more computer usable or computer-readablemedium(s) may be utilized. The computer-usable or computer-readablemedium may be, for example but not limited to, an electronic, magnetic,optical, electromagnetic, infrared, or semiconductor system, apparatus,device, or propagation medium. More specific examples (a non-exhaustivelist) of the computer-readable medium would include the following: anelectrical connection having one or more wires, a portable computerdiskette, a hard disk, a random access memory (RAM), a read-only memory(ROM), an erasable programmable read-only memory (EPROM or Flashmemory), an optical fiber, a portable compact disc read-only memory(CD-ROM), an optical storage device, a transmission media such as thosesupporting the Internet or an intranet, or a magnetic storage device.Note that the computer-usable or computer-readable medium could even bepaper or another suitable medium upon which the program is printed, asthe program may be electronically captured, via, for instance, opticalscanning of the paper or other medium, then compiled, interpreted, orotherwise processed in a suitable manner, if necessary, and then storedin a computer memory. In the context of this document, a computer-usableor computer-readable medium may be any medium that may contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The computer-usable medium may include a propagated data signal with thecomputer-usable program code embodied therewith, either in baseband oras part of a carrier wave. The computer usable program code may betransmitted using any appropriate medium, including but not limited towireless, wireline, optical fiber cable, RF, etc.

Computer program code for carrying out operations of the presentinvention may be written in any combination of one or more programminglanguages, including an object oriented programming language such asJava, Smalltalk, C++ or the like and conventional procedural programminglanguages, such as the “C” programming language or similar programminglanguages. The program code may execute entirely on a user's computer,partly on the user's computer, as a stand-alone software package, andpartly on the user's computer and partly on a remote computer orentirely on the remote computer or server. In the latter scenario, theremote computer may be connected to the user's computer through any typeof network, including a local area network (LAN) or a wide area network(WAN), or the connection may be made to an external computer (forexample, through the Internet using an Internet Service Provider).

The present invention is described below with reference to flowchartillustrations and/or block diagrams of methods, apparatus (systems) andcomputer program products according to embodiments of the invention. Itwill be understood that each block of the flowchart illustrations and/orblock diagrams, and combinations of blocks in the flowchartillustrations and/or block diagrams, may be implemented by computerprogram instructions. These computer program instructions may beprovided to a processor of a general purpose computer, special purposecomputer, or other programmable data processing apparatus to produce amachine, such that the instructions, which execute via the processor ofthe computer or other programmable data processing apparatus, createmeans for implementing the functions/acts specified in the flowchartand/or block diagram block or blocks.

These computer program instructions may also be stored in acomputer-readable medium that may direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablemedium produce an article of manufacture including instruction meanswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide processes for implementing the functions/actsspecified in the flowchart and/or block diagram block or blocks.

Referring now to FIG. 1, a service system 100 for authenticating asource of a telecommunication includes in general, a sender 110, ascreener 120, a subscriber 130, and an authenticator 140 coupled to adata bank 150 and computer 160. Generally speaking, there are variousways an entity may reach out to another party and some individualspossess various devices for being reached. Thus, the service system 100may provide a service applicable to various communication scenarios. Inone embodiment, the service will screen a sender 110, which may be atelephone caller wishing to telephone a subscriber 130 on thesubscriber's home telephone, business telephone, mobile phone orpersonal digital assistant (PDA). The screener 120 may be an individualor an automated screening function, which operates for instance, at atelephone-provider's hub. The authenticator 140 may also be anindividual or similar to the screener 120 may be automated to access adata bank 150. The sender 110, screener 120, authenticator 140, databank 150, computer 160 and subscriber 130 may all be interconnectedusing telecommunication lines 170. Additionally, the screener 120,authenticator 140, data bank 150, and computer 160 may be coupledtogether to form a network 180. In some embodiments, the screener 120may incorporate the components of the authenticator 140, data bank 150,and computer 160 and perform the functions of both the screener andauthenticator. The data bank 150 may hold information including senderor caller account information. In other embodiments, the subscriber canbe the screener, issue the challenge and call the authenticator toreceive it as a proof of caller's authentication.

In one exemplary embodiment, subscribers 130 may generate an accountwith the service system 100 that includes subscriber account informationincluding a list of authorized entities which may communicate with thesubscriber. Additionally, prospective callers/senders may generate anaccount with the service system 100, which includes registering thecaller's or sender's identity. Additionally, an account may include thecaller's phone number or sender's communication address. Registering anaccount may also include a showing of proof that the caller or sender isthe entity it claims to be. For example, a business entity such as abank that wishes to communicate with bank clients may register with theservice system 100 upon a providing a business license number, a phonenumber, utility bills or other similar reliable evidence of identity.Registering callers/senders may also then be issued a public encryptionkey or digital signature for encoding communications sent between thecaller/sender and the service system 100. The public encryption key ordigital signature may also be associated with a private key duringregistration so that encrypted communications may be securelytransmitted to the service system 100.

Thus, it will be appreciated that the service system 100 applies aninteraction by obliging callers/senders to demonstrate proof ofidentity. Referring now to FIG. 2, one exemplary embodiment operateswhen a caller 110 initiates a call directed to a subscriber 130 (step210). As the call is in transit to the subscriber 130, the screener 120intercepts the call (step 220). The screener 120 may check for calleridentification information including the source phone number of the calland/or request the caller to identify itself (step 230). Optionally,calls may be immediately dropped if they lack caller-identificationinformation, the caller refuses to identify itself, or are not on thelist of authorized callers the subscriber 130 has registered in itsaccount.

The screener 120 may then issue a challenge to the caller 110 (step240). Examples of a challenge may include an arbitrarily selected word,phrase, or number, presented during the call or a previously-designatedidentifier recorded during registration. The challenge may be presentedverbally over the phone or sent to another registered location such asthe caller's e-mail address or to a mobile phone capable of receivingshort message system messages (SMS). During the process, a softwareagent may be employed to automate the service system 100 by performingfunctions such as intercepting the call, recognizing and requestingcaller identification, issuing challenges, and forwarding the calls tothe subscriber 130. Other functions of the software agent may includeperforming speech-synthesis and speech-recognition tools to interactwith the caller 110. For example, the speech-synthesis tools may be usedto issue the challenge during the phone call. In another example, thespeech-recognition tools may be employed to recognize and retrievecaller account information from the authenticator 140 or data bank 150.Another embodiment may use the software agent to request the caller 110use touch tone input of information and the software agent may includetools to retrieve call account information based on the inputted touchtones.

The call may then be put on hold while the caller 110 may, outside ofthe call, take the challenge, encrypt the challenge using a private keyor attach the challenge in a message along with the caller's registereddigital signature and send the encrypted challenge to the authenticator140 through a secured telecommunication line 170 such as a website link(step 250). The caller 110 interfaces with the authenticator 140 (step260 a), presenting the encrypted challenge. The authenticator 140 mayretrieve the caller's account information from the data bank 150. Theauthenticator 140 may, with the aid of computer 160, decrypt thechallenge using a public key and/or compare the digital signatureattached with the challenge to a digital signature registered with thecaller's registration information. The authenticator 140 may perform allverifications or just decrypt the caller's 110 forwarded information.The screener 120 may then contact the authenticator 140 (step 260 b)where the authenticator forwards to the screener unencrypted informationincluding a proposed challenge, a caller identification and source phonenumber, and a digital signature.

The screener 120 may then verify the challenge received from theauthenticator 140 matches the challenge issued to the caller 110 duringthe call (step 270). Optionally, the screener 120 may also verify thatthe caller identification and phone number received from theauthenticator 140 match the caller identification and phone numberdisplayed by the caller 110 during the call. If the challenge is notverified, the screener 120 may block the call from reaching thesubscriber 130 and the call may be terminated (step 280). If thechallenge is verified, the screener 120 may then pass the call on to thesubscriber 130 (step 290).

Referring to FIG. 3, another exemplary embodiment is similar to the oneshown in FIG. 2 except that the call is interrupted after the challengeand the caller screener 120 may verify the source of the call by callingthe caller 110 back. The process may commence when a caller 110initiates a call directed to a subscriber 130 (step 310). As the call isin transit to the subscriber 130, the screener 120 intercepts the call(step 320). The screener 120 may check for caller identificationinformation including the source phone number of the call displayedusing caller ID tools (step 230). The screener 120 may request thecaller to identify itself verbally and request the phone number fromwhich it is calling from. The screener 120 verifies the phone numbergiven by the caller 110 matches the phone number displayed on the callerID and may also verify the phone number matches a number registered tothe caller during account registration (step 340). Once again, asoftware agent may be employed to automate the service system 100 byperforming functions such as intercepting the call, recognizing andrequesting caller identification, issuing challenges, recognizing inputby the caller, and forwarding the calls to the subscriber 130.Optionally, calls may be immediately dropped if they lackcaller-identification information or the caller refuses to identifyitself or is not on the list of authorized callers the subscriber 130has registered in its account.

The screener 120 may then issue a challenge to the caller 110 (step350). The challenge may, in one example, be given verbally. The screener120 then hangs up the call (step 350) and calls the caller 110 backusing the phone number supplied by the caller (step 360).

The screener 120 may then authenticate the caller 110 by verifying thecaller answers from the same phone number previously supplied andverifying that the caller is in possession of the challenge (step 370).The challenge may be recognized using the speech-recognition softwareand the software agent may compare the caller's input of the challengeto the challenge issued by the screener 120. If the challenge is notverified, the screener 120 may block the call from reaching thesubscriber 130 and the call may be terminated (step 380). If thechallenge is verified, the screener 120 may then pass the call on to thesubscriber 130 (step 390).

While the foregoing has been described primarily in the context ofscreening telephone calls, those skilled will understand that otherforms of telecommunication may likewise benefit from the invention andthus, the invention may equally be applied thereto. For example, theinvention may also be applied to e-mail messaging where the caller 110may be substituted for an e-mail sender and the subscriber 130 is ane-mail recipient. Thus, the screener 120 intercepts e-mail messages fromthe sender 110 to the recipient 130. The sender 110 may register ane-mail account including a source communication address and thechallenge can be sent to the e-mail account similarly as described inthe foregoing. Similarly, the same may be applied to screening out textmessages to one's mobile phone where a communication's sender mayregister with the service system 100 providing a source communicationaddress before sending SMS messages to a subscriber 130's mobile phone.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, may be implemented by special-purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

It should be understood, of course, that the foregoing relates toexemplary embodiments of the invention and that modifications may bemade without departing from the spirit and scope of the invention as setforth in the following claims.

We claim:
 1. A method of authenticating a source of a call from a callerto a recipient in a screening service, comprising: generating a calleraccount with the service including registration of a caller identity andregistration of a digital signature associated with the caller;recording the registered caller identity and the digital signature withan authenticator; intercepting the call by a screener; receiving aproposed caller identity by the screener from the caller during the callincluding a phone number associated with the source of the caller;issuing a challenge by the screener to the caller; sending a returnphone call from the screener to the caller using the phone number shownin the caller identity; verifying that the caller is in possession ofthe challenge; in response to verifying that the caller is in possessionof the challenge, encrypting the issued challenge and the proposedcaller identity by the caller using the digital signature; sending theencrypted challenge and the proposed caller identity from the caller tothe authenticator; decrypting the encrypted challenge and the proposedcaller identity at the authenticator and authenticating the source ofthe encrypted challenge by comparing the digital signature sent with theencrypted challenge against the digital signature registered in thecaller account; forwarding the decrypted challenge and the proposedcaller identity to the screener; verifying the decrypted challenge andthe caller's registered caller identity match the issued challenge andthe proposed caller identity received during the call; and passing thecall to the recipient.
 2. The method of authenticating a source of acall of claim 1, wherein the step of generating an account includesproviding proof of the caller identity.
 3. The method of authenticatinga source of a call of claim 1, wherein the step of sending the encryptedchallenge includes sending said challenge through a computer network tothe authenticator.
 4. The method of authenticating a source of a call ofclaim 1, wherein the step of issuing the challenge is done by sending ashort message system message from the screener to the phone numberassociated with the source of the caller in the proposed calleridentity.
 5. The method of authenticating a source of a call of claim 1,wherein the screener also performs the steps of the authenticator. 6.The method of authenticating a source of a call of claim 1, wherein asubscriber performs the steps of the screener.
 7. The method ofauthenticating a source of a call of claim 1, wherein the screenerissues a verbal challenge of one or more words over a voice channel andthe step of verifying the decrypted challenge comprises the screenercalling the authenticator, listening to the voiced message and verifyingthe proposed caller identity with the challenge.
 8. The method ofauthenticating a source of a call of claim 1, wherein the step ofdecrypting the challenge further includes verifying the proposed calleridentity and the phone number associated with the source of the callermatch the caller account.
 9. The method of authenticating a source of acall of claim 1, wherein: the step of generating a caller accountincludes registering an e-mail address; and the step of issuing thechallenge is sent via e-mail to the registered caller e-mail address.10. The method of authenticating a source of a call of claim 1, whereinthe challenge is issued from the screener to the caller using a speechsynthesis.
 11. The method of authenticating a source of a call of claim1, wherein the step of receiving the caller identity utilizes a speechrecognition software to identify the caller account.
 12. The method ofauthenticating a source of a call of claim 1, wherein the step offorwarding the decrypted challenge and caller ID from the authenticatorto the screener is performed using text messaging.
 13. A method ofauthenticating a source of a call from a caller to a recipient in ascreening service, including: intercepting the call by a screener;receiving a caller identity by the screener from the caller; verifyingthat the caller is registered to a phone number shown in the calleridentity; issuing a challenge by the screener to the caller and hangingup the call; sending a return phone call from the screener to the callerusing the phone number shown in the caller identity; verifying thecaller is in possession of the challenge; and passing the caller to therecipient.
 14. The method of authenticating a source of a call of claim13, wherein the step of receiving the caller identity includes askingthe caller to identify itself and recognizing the caller identity usingspeech recognition software.
 15. The method of authenticating a sourceof a call of claim 13, wherein; the step of receiving the calleridentity includes requesting the caller to use a touch tone input forinputting a call back number; and the step of verifying the caller isregistered to the phone number shown in the caller identity includesverifying the inputted call back number matches the phone number shownin the caller identity.
 16. The method of authenticating a source of acall of claim 15, wherein the step of verifying the caller is registeredto the phone number shown in the caller identity results in the inputtedcall back number not matching the phone number shown in the calleridentity and dropping the call.
 17. The method of authenticating asource of a call of claim 13, wherein: the step of verifying the calleris in possession of the challenge includes a verbal input of thechallenge by the caller during the return phone call; the screener usinga speech recognition software to recognize the verbal input of thechallenge; and a software agent for comparing the verbal input of thechallenge with the challenge issued by the screener.
 18. The method ofauthenticating a source of a call of claim 13, further comprisingdropping the call if the call lacks a caller identity.
 19. A tangiblecomputer readable medium comprising computer-usable program codeembodied therein for authenticating a source of a communication from asender to a recipient using a screening service, the computer-usableprogram code being configured to: generate a sender account senderregistration service information with the service including registrationof a sender identification, a sender communication address a senderpublic key and a sender private key; store the sender registrationinformation with an authenticator; intercept the communication by usinga screener; receive from the sender the sender identification and thesender communication address; issue an electronic challenge from thescreener to the sender; send a return phone call from the screener tothe sender verify the sender is in possession of the challenge; inresponse to verifying that the sender is in possession of the challenge,encrypt the electronic challenge using the sender private key, encryptedby the sender; receive the encrypted electronic challenge by theauthenticator from the sender; apply the registered sender public key tothe sender private key of the encrypted electronic challenge to decryptthe encrypted electronic challenge; block the communication if the stepof applying the registered sender public key to the private key of theencrypted electronic challenge fails to decrypt the challenge; forwardthe decrypted electronic challenge to the screener; verify with thescreener the decrypted electronic challenge matches the challenge issuedby the screener; and route the call to the recipient.
 20. A system forauthenticating a source of a telecommunication from a sender sent to asubscriber, comprising: a data bank configured to store subscriberinformation and sender registration data; a screener in electronicintermediate communication between the sender and the subscriber forintercepting the telecommunication, issuing a challenge to the senderand forwarding authenticated telecommunications to the subscriber,wherein the screener is configured to send a return phone call from thesubscriber to the sender and verify that the sender is in possession ofthe challenge; an authenticator in electronic communication with thedata bank and screener configured to, in response to verifying that thesender is in possession of the challenge, authenticate the source of thetelecommunication by comparing the sender registration data stored inthe data bank to an encrypted message transmitted from the senderincluding the challenge issued by the screener and for forwarding anauthentication status to the screener; and telecommunication linesconfigured to a telecommunication network between the sender, thescreener, the authenticator, the data bank, and the subscriber.
 21. Thesystem for authenticating a source of a telecommunication of claim 20,wherein the screener includes a computer incorporating a software agentfor automating the interception of the telecommunication, the issuanceof the challenge, and the forwarding of authenticated telecommunicationsto the subscriber.
 22. The system for authenticating a source of atelecommunication of claim 21, wherein the software agent includes ashort message system service for issuing the challenge over thetelecommunication lines using a short message system protocol.
 23. Thesystem for authenticating a source of a telecommunication of claim 21,wherein the software agent includes an e-mail service for issuing thechallenge over the telecommunication lines using an e-mail message.